Hello.
I've recently purchased a notebook model HP 15-bs018nu, it works quite well, but I have an issue with the display brightness. The issue is, that whenever I boot anything other than Windows or Linux, the display brightness is reset to something dim and I cannot control it. It is so dimm that under daylight conditions it is very difficult to read.
I am an OS developer and I often boot and run my own protected mode OS on the machine. I don't have any clue if I can modify my OS so as to change the brightness. Perhaps I should write some values to some ports? Or invoke real mode BIOS some how? From real mode, from protected mode?
Perhaps if I upgrade the notebook BIOS I would then be able to control the display brightness from the keyboard?
Or maybe it is stored in CMOS RAM somewhere?